Understanding and debugging program code often involves browsing, searching, and stepping through a number of program code files. For example, a user may browse search results or explore definition graphs. Typically, when a file is opened in an Integrated Development Environment (IDE), the IDE adds the file as a tab to the collection of tabs displayed on a display screen. This approach assumes that most of the files that are open will be found useful by the user. However, users can find that so many files have been opened that it becomes difficult to keep track of what files are open and what is of interest in the open files. This can be especially true for a user who is working with unfamiliar code.